Conventional airbags frequently comprise multiple panels of fabric cut to particular patterns and assembled at their peripheries by seams. Some such fabric panels are uncoated. Others, including versions provided by the assignee of this application, may be coated with highly-impermeable silicone to reduce leakage of inflation gas through the panels. Reducing gas leakage from an airbag greatly enhances its performance, as pressure within the bag from the gas-generation event may be sustained for longer periods.
U.S. Pat. No. 6,364,356 to Keshavaraj details methods of forming an exemplary inflatable airbag. Panels may be adhered together by welded seams, with the welding purportedly “reducing air or gas permeability.” See Keshavaraj, Abstract, 11. 5-6. As described in the Keshavaraj patent, “a single stitched (sewn) seam located adjacent” two welded seams may “provide increased tear strength” for the combined seam structure. See id., col. 6, 11. 8-9 (numeral omitted).
Although utilizing multiple seams for inflatable fabrics may reduce gas permeability of the panels, significant gas leakage may continue to occur. Likewise, although employing multiple seams may provide greater tear strength, as indicated in the Keshavaraj patent, substantial reinforcement of seams may continue to be required. Accordingly, need exists for materials adapted to provide reduced permeability of, and greater strength to, seams of fabric panels.